EP 1377070 A4 20100811 - QUANTIZATION APPARATUS, QUANTIZATION METHOD, QUANTIZATION PROGRAM, AND RECORDING MEDIUM
Title (en)
QUANTIZATION APPARATUS, QUANTIZATION METHOD, QUANTIZATION PROGRAM, AND RECORDING MEDIUM
Title (de)
QUANTISIERUNGSVORRICHTUNG, QUANTISIERUNGSVERFAHREN, QUANTISIERUNGSPROGRAMM UND AUFZEICHNUNGSMEDIUM
Title (fr)
APPAREIL, PROCEDE, PROGRAMME DE QUANTIFICATION ET SUPPORT D'ENREGISTREMENT
Publication
Application
Priority
- JP 0203061 W 20020328
- JP 2001091757 A 20010328
Abstract (en)
[origin: EP1377070A1] A rounding accuracy of DCT coefficients that are quantized is dynamically varied with a simple structure. As a result, an encoding noise is effectively suppressed and the picture quality is prevented from being deteriorated. DCT coefficients of which a picture signal is transformed by DCT are input to a quantizing circuit 30. The quantizing circuit 30 quantizes the DCT coefficients with a quantizer matrix and supplies the quantized DCT coefficients to a multiplying device 33 through an absolute value circuit 31. A quantizer scale value based on the generated code amount of the entire screen is converted into an invert value thereof and then supplied to a multiplying device 33. In addition, an M value designating circuit 38 designates a value M as a parameter with which a rounding accuracy of DCT coefficients that are quantized is controlled according to a quantizer scale value. An adding device 34 adds the value M to an output of the multiplying device 33. A five-bit shifting circuit 35 rounds off a decimal part. At that point, as the quantizer scale value becomes large, the rounding accuracy of DCT coefficients that are quantized is designated so that the round off direction becomes large. Thus, the DCT coefficients are quantized so that the amplitude is not increased. As a result, the encoding noise can be suppressed. <IMAGE>
IPC 8 full level
CPC (source: EP KR US)
H04N 19/124 (2014.11 - KR); H04N 19/126 (2014.11 - EP US); H04N 19/15 (2014.11 - EP US); H04N 19/174 (2014.11 - EP US); H04N 19/61 (2014.11 - EP US)
Citation (search report)
- [X] US 5374958 A 19941220 - YANAGIHARA HAOFUMI [JP]
- [XI] WO 9838800 A1 19980903 - BRITISH BROADCASTING CORP [GB], et al
- [XPI] US 6275527 B1 20010814 - BIST ANURAG [US], et al
- [XI] EP 0933947 A2 19990804 - XEROX CORP [US]
- See references of WO 02080573A1
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
EP 1377070 A1 20040102; EP 1377070 A4 20100811; JP WO2002080573 A1 20040722; KR 20030086331 A 20031107; US 2004086192 A1 20040506; US 7286715 B2 20071023; WO 02080573 A1 20021010; WO 02080573 A9 20030724
DOCDB simple family (application)
EP 02707218 A 20020328; JP 0203061 W 20020328; JP 2002577444 A 20020328; KR 20037012664 A 20030927; US 47302903 A 20030925